Mandrel locking mechanism



y 1967 J. GERRITTS MANDREL LOCKING MECHANISM I INVENTOR" KENNETH J. GERRITS Filed Aug. 11, 1966 United States Patent 3,331,565 MANDREL LGCKING MECHANISM Kenneth J. Gerritts, West De Pere, Wis., assignor to Paper Converting Machine (30., Inc., Green Bay, Wis, a corporation of Wisconsin Filed Aug. 11, 1966, Ser. No. 571,832 Claims. (Cl. 242-721) This invention relates to a mandrel locking mechanism and, more particularly, to a mandrel utilized for the winding of webs at high speed.

This application is a continuation-in-part of my copending application Ser. No. 352,889, filed Mar. 18, 1962, now abandoned. Reference may be made to the above-identified application for additional details of construction not found herein.

The mandrel with which the instant invention is concerned is utilized advantageously in connection with high speed Winders. A detailed showing of such a winder can be seen in the co-owned patent of Kwitek and Nystrand, No. 2,769,600. Such winders are conventionally employed for the winding webs of toweling or toilet tissue into retail-size rolls. These winders are of the continuous type, i.e., being adapted to operate at a relatively high speed without slowdown or interruption when a given retail size web roll is completed. For this purpose, the Winder is equipped with a turret which contains a plurality of mandrels which index in an orbit so as to have a mandrel ready to take up the winding operation when a previous mandrel has completed its winding cycle. An appreciation of the problems involved can be gained from the fact that winders are now intended to function at speeds of the order of 3,000 feet per minute. This requires that the mandrel operate at speeds of the order of 8,000 r.p.rn., developing tremendous centrifugal forces. Further, a given winding cycle is relatively short. The toilet tissue roll being developed on a winder utilizing the inventive mandrel may have a 500 count, i.e., 500 detachably connected squares 4 /2 inches on a side. With such an operation a given roll is wound in 3% seconds.

Prior to entering this relatively short time cycle, the mandrel is ensleeved with a cardboard core. This core is equipped with adhesive for coupling the leading edge portion of the relatively flimsy web to the core, and if a properly wound Web roll is to be developed, the core must be immobilized, i.e., fixed against movement both rotational and axial, to the mandrel or core shaft. These mandrels or core shafts generally have lengths in excess of 90 inches so as to develop a plurality of 4 /2 inch wide rolls in a given winding cycle. For example, a mandrel having a length sufiicient to receive a 90-inch core is designated a 20 wide mandrel. Currently, the practice is to develop a web log of say 90 inches length, and transversely sever it subsequent to winding. This has led the art to provide a rather compact locking mechanism as contrasted to one extending over substantially the entire length of the mandrel. The multiple locking feature can be seen, for example, in Nystrand Patent No. 2,901,192. With the use of a compact locking mechanism, i.e., one restricted to a relatively short length of the mandrel, a problem has arisen. Since the gripping must be sufficiently strong to compensate for the heretofore distributed gripping, the tendency of the gripping, the tendency of the gripping mechanism to react unfavorably to centrifugal force has increased. Also it should be appreciated that expedients of any complex nature are undesirable since these increase the likelihood of dynamic unbalance which could cause failure quite readily at the speeds encountered.

The foregoing problem has been solved by the inventive mandrel locking mechanism and the provision of a solution thereto constitutes an important object of the in- 3,331,555 Patented July 18, 1967 vention. Other objects and advantages of the invention may be seen in the details of construction and operation set down in this specification.

The invention is explained in conjunction with an illustrative embodiment, in the accompanying drawing, in which FIG. 1 is a fragmentary sectional view of a mandrel embodying teachings of the instant invention;

FIG. 2 is an enlarged cross-sectional view taken along the line 22 of FIG. 1;

FIG. 3 is a fragmentary side elevational view such as would be seen along the sight line 33 applied to FIG. 2; and

FIG. 4 is an enlarged fragmentary detailed showing of a portion of the locking mechanism seen in FIG. 1.

In the drawing, and with particular reference to FIG. 1, the numeral 10 designates generally a mandrel constructed according to the teachings of this invention. The mandrel is seen to be equipped with a core receiving end 11 and a support end 12.

For the purpose of clarity of illustration, details of the supporting frame and mandrel driving mechanism have been omittedin their stead, only schematic representations illustrated as at 13 relative to the frame and 14 relative to the drive. The frame and drive can be seen in a preferred version in Nystrand Patent No. 2,995,3 14. In the usual operation, the mandrel is cantilever-supported at the end 12 for receipt of a core introduced over the end 11. After the core has been received on the mandrel, the drive 14 which may take the form of a belt and pulley system, is energized so as to bring the mandrel 10 up to speedat this time in the cycle, the end 11 being received in suitable journal blocks, so as to convert the cantilever support to a double end support. After being double supported, the core is equipped with adhesive. This double support continues throughout the winding cycle, the mandrel 10 having its highest speed at the beginning of the winding cycle and when the diameter of the web roll to be developed on the core is minimal. The angular velocity of the mandrel decreases during the winding cycle to accommodate a constant speed web feed. After the winding cycle is complete, the mandrel 10 is once again cantilever mounted, the locking mechanism deactivated and the now-completed web log removed over the end 11. Even though it will be appreciated that although the mandrel in a six mandrel turret may only be involved in winding for 4 seconds, all of the ensleeving and removal operations must be performed rapidly, since the mandrel must again be in position for a subsequent winding in about 19 seconds.

When the core (as at C in FIG. 3) is ensleeved on the mandrel 10 past the locking mechanism generally designated 15 (see FIG. 1), the actuator 16 (see the extreme lefthand portion of FIG. 1), is allowed to extend axially outwardly of the mandrel 10 to the dotted line position is. This is conveniently achieved by use of a camming surface (not shown) provided as part of the frame 13. The extension of the actuator 16 has the effect of moving the conical bearing surface 17 to the left and urging the arcuate segments 18 radially outwardly into gripping relation with the core C.

For accommodating the actuating mechanism, the mandrel 10 adjacent the end 12 is equipped with a hollow bore as at 19 which receives the conical element 17. The element 17 is pinned as at 20 to a longitudinally-extending shaft 21 mounted in the bore 19. The shaft 21 is supported additionally by means of a longitudinally-fixed bearing block 22, and a slidable bearing block 23-the slidable bearing block 23 being pinned to the shaft 21 by means of a pin 24. The lefthand end 25 of the shaft 21 is seen to be threaded and thus secured within a threaded bore 26 provided in the actuator 16. Interposed between the stationary and movable bearing blocks 22 and 23, respectively, is a coil spring 27. Thus, when the actuator 16 is moved into the mandrel by virtue of the camming surface (not shown), the spring 27 is compressed and is available to provide energy to move the shaft 21 to the left when the engagement of the actuator 16 with the camming surface is relieved.

Movement of the shaft to the left (in the illustration given) results in the movement of the conical surface element 17 to the left and the engagement thereof with bullet-shaped projections 28 extending radially inwardly from the gripping segments 18. Each bullet-shaped projection, i.e., one having a radially inwardly facing spherical surface, is secured to its associated arcuate segment by means of a rivet 29. The arcuate segments 18 are advantageously equipped with knurled surfaces as at 30 (compare FIGS. 2 and 3), and in the illustration given, extend over an arc of the order of 120. Further, the segments 18 are circumferentially grooved as at 31 so as to receive O-rings 32 which restrain the segments in a position such that the core gripping surface is below the mandrel diameter to facilitate loading the core onto the mandrel and over the core gripping segments. The mandrel body as at 33 (see the central upper portion of FIG. 1) is suitably radially bored as at 34 for the purpose of receiving and mounting the projections 28. Also, as can be seen in FIG. 4, the outer wall of the body 33 is recessed as at 35 so as to accommodate the segments 18 in what might be considered a substantially flush mounting, thereby facilitating the ensleeving of the core C.

The use of the O-rings 32 is inadequate to oppose centrifugal forces developed by the speed of the mandrel, and for opposing this force, I provide a locking feature which includes a recess 36 (see FIGS. 2-4), in the outer portion of each projection 28'. The recess or notch 36 is arranged to receive a washer 37 (see FIGS. 3 and 4) which is secured within the body 33 by means of a screw 38. To facilitate the assembly of the parts just referred to, the segments 18 each are equipped with a screwdriver access hole as at 39. In the assembly of the elements, the projection 23 is initially riveted or otherwise secured to the segment 18' and the washer 37 and screw 38 placed in position on the inner face of the segment 18,'being retained thereon by virtue of the insertion of a screwdriver (not shown) into the access opening 39. Thereafter, the bullet-shaped projection 28 is inserted within the radial bore 34 and the screwdriver employed to seat the screw 38 and thus the washer 37 in the position indicated in FIG. 4. Thereafter, during high-speed operation, any tendency of the segment 18 to leave the mandrel body 33 by virtue of excessive centrifugal forces, is mechanically resisted by engagement of the washer 37 by the inner wall 36a of the recess or notch 36. Thus a positive lock or bar is provided against inopportune disassembly of the mandrel locking mechanism.

In the operation of the device 10, I find it advantageous to provide a stroke, i.e., movement of the actuator 16 of the order of 93 inch between full extension and full retraction. Further, a substantial movement of the segments 18 can be permitted, the length of the recess 36 (in a radial direction) being of the order of & inch. The overall length of the projection 28 is of the order of 0.68 inch with the outer W inch being devoted to providing integral rivet 29.

While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of explanation, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. A core-locking mechanism comprising. a frame, means on said frame for moving a mandrel into and out of web-winding position and for rotating the same when said mandrel is in web-winding position, an elongated mandrel rotatively mounted at one end on said frame so as to provide a core-receiving end at the other end thereof, said mandrel being equipped with a longitudinallyextending bore extending part way therealong from said one end, an actuator rod mounted for reciprocation within said bore, said mandrel having an annular recess in its outer surface, a plurality of circumferentially extending arcuate segments in said recess, each segment being equipped with a radially inwardly extending projection with said projections being simultaneously engageable by said rod to urge said segments outwardly into engagement with a core ensleeved on said mandrel, and unyielding means on said mandrel within said annular recess selectively engageable with said projections for limiting the radially outward movement of said segments to a predetermined distance beyond said recess.

2. The structure of claim 1 in which each of said projections is equipped with a notch in an outer wall thereof, said mandrel being equipped with a rigid element constituting said unyielding means for engagement with the wall of said notch.

3. The structure of claim 2 in which each of said segments is equipped with a radiallyextending passage constituting an access opening, said rigid element including a washer secured to said mandrel by screw means, said screw means and segment access passage being aligned.

4.'The structure of claim 1 in which said segments are circumferentially recessed, and O-ring means mounted in encircling relation relative to said segments.

5. The structure of claim 1 in which said projections have bullet-shapes at their inner ends, said actuator rod being equipped with a conical segment for simultaneous actuation of said bullet-shaped projections.

7 References Cited UNITED STATES PATENTS 372,533 12/1907 Paquette 242-721 2,297,648 9/1942 Cushman 242-721 FOREIGN PATENTS 351,498 8/1937 Italy.

FRANK J. COHEN, Primary Examiner. N. L. MINTZ, Assistant Examiner. 

1. A CORE-LOCKING MECHANISM COMPRISING A FRAME, MEANS ON SAID FRAME FOR MOVING A MANDREL INTO AND OUT OF WEB-WINDING POSITION AND FOR ROTATING THE SAME WHEN SAID MANDREL IS IN WEB-WINDING POSITION, AN ELONGATED MANDREL ROTATIVELY MOUNTED AT ONE END ON SAID FRAME SO AS TO PROVIDE A CORE-RECEIVING END AT THE OTHER END THEREOF, SAID MANDREL BEING EQUIPPED WITH A LONGITUDINALLYEXTENDING BORE EXTENDING PART WAY THEREALONG FROM SAID ONE END, AN ACTUATOR ROD MOUNTED FOR RECIPROCATION WITHIN SAID BORE, SAID MANDREL HAVING AN ANNULAR RECESS IN ITS OUTER SURFACE, A PLURALITY OF CIRCUMFERENTIALLY EXTENDING ARCUATE SEGMENTS IN SAID RECESS, EACH SEGMENT BEING EQUIPPED WITH A RADIALLY INWARDLY EXTENDING PROJECTION WITH SAID PROJECTIONS BEING SIMULTANEOUSLY ENGAGEABLE BY SAID ROD TO URGE SAID SEGMENTS OUTWARDLY INTO ENGAGEMENT WITH A CORE ENSLEEVED ON SAID MANDREL, AND UNYIELDING MEANS ON SAID MANDREL WITHIN SAID ANNULAR RECESS SELECTIVELY ENGAGEABLE WITH SAID PROJECTIONS FOR LIMITING THE RADIALLY OUTWARD MOVEMENT OF SAID SEGMENTS TO A PREDETERMINED DISTANCE BEYOND SAID RECESS. 